The leg is hit by a car and there is a lump, after drawing blood, there may still be a lump. Lump in the leg after being hit by a car is caused by external stimulation of subcutaneous bruising, or soft tissue congestion and swelling, if a hematoma is formed, blood can be drawn, and after drawing blood, due to the local soft tissue congestion and swelling, there may still be a lump. If the leg is hit by a car and there is a lump, an imaging test should be done to determine whether there is a fracture, bone fracture and other bone abnormalities. If the bones are normal and there is only soft tissue swelling or subcutaneous bruising, most of them can be gradually absorbed and dissipated with symptomatic treatment. Cold compresses are applied within 48 hours after trauma, mainly to constrict blood vessels and reduce edema. 48 hours later, when bleeding has stopped, hot compresses can be applied to promote circulation and the absorption and dissipation of edema. For those who have hematoma formation and the effect of conservative treatment is not good, they can be treated with blood sampling and pressure bandage, and those who form hematoma mechanization also need surgical incision to remove it.